Chapter 20

Question 1

what is the fundamental function of the heart?

Answer 1

the heart acts as a pump, producing the force that causes blood to circulate

Question 2

what is the pericardium and what is it made up of?

Answer 2

a sac that surrounds the heart
consists of the fibrous and the serous pericardium

Question 3

what is the function of the fibrous pericardium?

Answer 3

it helps hold the heart in place

Question 4

what is the function of the serous pericardium?

Answer 4

it reduces friction as the heart beats

Question 5

what does the serous pericardium consist of?

Answer 5

the parietal pericardium, visceral pericardium and pericardial cavity

Question 6

name the 3 layers of the heart wall

Answer 6

the outer epicardium (visceral pericardium), the middle myocardium and inner endocardium

Question 7

describe the functions of each layer of the heart

Answer 7

outer epicardium- provides protection against friction of rubbing organs
middle myocardium- responsible for contraction
inner endocardium- reduces friction from blood passing through heart

Question 8

the muscular ridges in auricles are called:

Answer 8

pectinate muscles

Question 9

the muscular ridges in ventricles are called:

Answer 9

trabeculae carneae

Question 10

an atrial flap is called:

Answer 10

an auricle

Question 11

what separates the atria from the ventricles?

Answer 11

the coronary sulcus

Question 12

what structures enter the right atrium?

Answer 12

inferior and superior vena cavae
coronary sinus

Question 13

what structures enter the left atrium?

Answer 13

the four pulmonary veins

Question 14

what structures exit the right and left ventricles respectively?

Answer 14

right ventricle- pulmonary artery
left ventricle- aorta

Question 15

what structures separate the atria and ventricles from one another?

Answer 15

atria- the interatrial septum
ventricles- the interventricular septum

Question 16

which valve separates the right atrium from the right ventricle?

Answer 16

the tricuspid valve

Question 17

which valve separates the left atrium from the left ventricle?

Answer 17

the bicuspid/mitral valve

Question 18

how are muscles attached to the atrioventricular valves?

Answer 18

the chordae tendineae
attach the papillary muscles
to the atrioventricular valves

Question 19

which valves separate the aorta and pulmonary trunk from the ventricles?

Answer 19

the semilunar valves

Question 20

what is the route of blood flow of blood from the body?

Answer 20

vena cavae, right atrium, right ventricle, pulmonary artery, lungs

Question 21

what is the route of blood flow from the lungs?

Answer 21

pulmonary vein, left atrium, left ventricle, aorta, body

Question 22

list some key histological features of cardiac muscle

Answer 22

-branched and striated
-centrally located nucleus
-actin and myosin organised to form sarcomeres
-cells joined by intercalated disks
-APs pass from one cell to another through gap junctions
-well supplied with blood vessels
-aerobically respire to form ATP

Question 23

where are the SA (sinoatrial) and AV (atrioventricular) nodes located?

Answer 23

in the right atrium

Question 24

how is the AV node connected to the bundle branches in the interventricular septum?

Answer 24

by the AV bundle

Question 25

what structure do the bundle branches give rise to?

Answer 25

the Purkinje fibers

Question 26

list the key structure of the heart in the order an action potential passes through them

Answer 26

-SA node -AVN -Bundle of His -Purkinje fibres

Question 27

the term for the spontaneous development of a pacemaker potential from cardiac pacemaker muscle cells is:

Answer 27

autorhythmic

Question 28

the pacemaker potential results from the movement of:

Answer 28

sodium and calcium into the pacemaker cells

Question 29

what are ectopic foci?

Answer 29

areas of the heart that regulate heart rate under abnormal conditions

Question 30

the movement of which ions cause depolarisation in cardiac muscle cells?

Answer 30

sodium ions through voltage-gated sodium channels

Question 31

which voltage-gated channels are open and closed during depolarisation of a cardiac muscle cell?

Answer 31

-sodium channels open -potassium channels closed -calcium channels begin to open

Question 32

repolarisation of a cardiac muscle cell is the result of:

Answer 32

closure of VG sodium channels and opening of VG potassium channels

Question 33

why does the plateau during an action potential in a cardiac muscle cell exist?

Answer 33

voltage gated calcium channels remain open

Question 34

rapid repolarisation results from:

Answer 34

closure of VG calcium channels and opening of some VG potassium channels

Question 35

the entry of calcium into cardiac muscle cells causes:

Answer 35

calcium to be released from the sarcoplasmic reticulum to cause contractions

Question 36

cardiac muscle has prolonged depolarisation and thus a prolonged refractory period. what does this allow for?

Answer 36

allows the cardiac muscle time to relax before the next action potential causes a contraction

Question 37

an ECG records:

Answer 37

the electrical activity of the heart

Question 38

which phase produces the P wave?

Answer 38

depolarisation of the atria

Question 39

which phase produces the QRS complex?

Answer 39

depolarisation of the ventricles

Question 40

repolarisation of the atria occurs during:

Answer 40

the QRS complex

Question 41

which phase produces the T wave?

Answer 41

repolarisation of the ventricles

Question 42

ECGs can be used to diagnose heart abnormalities based on:

Answer 42

-magnitude of ECG waves -time between waves

Question 43

an ECG would not be able to diagnose a heart murmur because:

Answer 43

heart murmurs are detected by listening to heart sounds

Question 44

activity in which valves cause the 1st heart sound?

Answer 44

closure of the atrioventricular valves

Question 45

activity in which valves cause the 2nd heart sound?

Answer 45

closure of the semilunar valves

Question 46

a 3rd heart sound may be produced due to:

Answer 46

turbulent flow of blood into the ventricles

Question 47

mean arterial blood pressure is:

Answer 47

the average blood pressure in the aorta

Question 48

mean arterial pressure is proportional to:

Answer 48

cardiac output x peripheral resistance

Question 49

define cardiac output

Answer 49

amount of blood pumped by the heart per minute

Question 50

define peripheral resistance

Answer 50

total resistance to blood flow through blood vessels

Question 51

cardiac output is equal to:

Answer 51

stroke volume x heart rate

Question 52

define stroke volume

Answer 52

amount of blood pumped by the heart per beat

Question 53

stroke volume is equal to:

Answer 53

end diastolic volume - end systolic volume

Question 54

how does increased venous return increase stroke volume?

Answer 54

by increasing end diastolic volume

Question 55

how does increased force of contraction increase stroke volume?

Answer 55

by decreasing end systolic volume

Question 56

what is cardiac reserve?

Answer 56

the difference between resting and exercising cardiac output

Question 57

what is venous return?

Answer 57

the amount of blood that returns to the heart during each cardiac cycle

Question 58

what does the Starling Law of the heart describe?

Answer 58

the relationship between preload and the stroke volume of the heart

Question 59

which part of the brain regulates parasympathetic and sympathetic nervous control of the heart?

Answer 59

the cardioregulatory center in the medulla oblongata

Question 60

parasympathetic stimulation is supplied by:

Answer 60

the vagus nerve

Question 61

how does parasympathetic stimulation affect heart rate?

Answer 61

decreases heart rate

Question 62

describe parasympathetic stimulation's role in heart regulation

Answer 62

-postganglionic neurons secrete ACh (acetylcholine) -increases membrane permeability to potassium -causes hyperpolarisation of the membrane

Question 63

sympathetic simulation is supplied by:

Answer 63

the cardiac nerves

Question 64

how does sympathetic stimulation affect heart rate?

Answer 64

increases heart rate (as well as force of contraction/stroke volume)

Question 65

describe sympathetic stimulation's role in heart regulation

Answer 65

-postganglionic neurons secrete norepinephrine -increases membrane permeability to sodium and calcium -causes depolarisation of the membrane

Question 66

from which location are epinephrine and norepinephrine released?

Answer 66

into the blood from the adrenal medulla

Question 67

how do epinephrine and norepinephrine affect the heart?

Answer 67

-increase heart rate and force of contraction -long-lasting effects compared to neural stimulation

Question 68

what do baroreceptors monitor?

Answer 68

blood pressure

Question 69

how do baroreceptors respond to a decrease in blood pressure?

Answer 69

-increase sympathetic stimulation -decrease parasympathetic stimulation -increasing heart rate and force of contraction

Question 70

what do chemoreceptors monitor?

Answer 70

-blood CO2 levels -blood O2 levels -blood pH levels

Question 71

how do medullary chemoreceptors respond to increased blood CO2 and decreased blood pH?

Answer 71

-increase sympathetic stimulation -decrease parasympathetic stimulation

Question 72

which type of chemoreceptor is stimulated by low O2 levels and what does this result in?

Answer 72

-carotid body chemoreceptor -result in decreased heart rate and vasoconstriction

Question 73

what is the effect of an increase or decrease in extracellular potassium on heart rate?

Answer 73

decreased heart rate

Question 74

what are the effects of increased extracellular calcium on the heart?

Answer 74

-increased force of contraction -decreased heart rate

Question 75

what are the effects of body temperature on heart rate?

Answer 75

-increased temperature increased heart rate -decreased temperature decreased heart rate